Oracle 视图 ALL_IMMUTABLE_TABLES 官方解释，作用，如何使用详细说明
本站中文解释
Oracle视图ALL_IMMUTABLE_TABLES是提供Oracle数据库技术支持时常用的一个只读视图，用于跟踪、显示和管理所有的不可变的数据库表。所有不可变的表是指系统在它们被编号或称之为块的过程中(以及写入任何实体数据之前以后)不再更改的表。它们不能被处理的任何行更新、删除、插入、清除和其它更改;相反，它们仅适用于查询处理。ALL_IMMUTABLE_TABLES视图以它们被称为不可变的时间以及计算系统表(IOT)表及普通表显示出来。
使用ALL_IMMUTABLE_TABLES视图非常简单，只需直接使用它即可。它用于监视系统中所有不可变的表，也可以用于限制某些语句的执行，以防止由于某些表已变得不可变而未被处理。例如，可以使用ALL_IMMUTABLE_TABLES视图来查询特定表上的行计数:
SELECT ROWS_COUNT FROM ALL_IMMUTABLE_TABLES WHERE TABLE_NAME = ‘MY_TABLE’;
官方英文解释
ALL_IMMUTABLE_TABLES describes the immutable tables accessible to the current user.
Related Views
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DBA_IMMUTABLE_TABLESdescribes all immutable tables in the database. -
USER_IMMUTABLE_TABLESdescribes the immutable tables owned by the current user. This view does not display theSCHEMA_NAMEcolumn.
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The schema containing the immutable table |
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Name of the immutable table |
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Row retention period for the immutable table, that is, the minimum number of days a row must be retained and cannot be deleted after it is inserted into the table If the value of this column is NULL, then rows can never be deleted from the table. |
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Indicates whether the row retention period for the immutable table is locked. Possible values:
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Number of days for which the immutable table must be inactive before it can be dropped, that is, the number of days that must pass after the most recent row insertion before the table can be dropped A table with no rows can be dropped at any time, regardless of this column value. |
See Also:
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“DBA_IMMUTABLE_TABLES”
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“USER_IMMUTABLE_TABLES”
